Goto Section: 90.375 | 90.379 | Table of Contents
Revised as of October 20, 2020
Goto Year:2020 |
§ 90.377 Frequencies available; maximum EIRP and antenna height, and
(a) Licensees shall transmit only the power (EIRP) needed to
communicate with an On-Board Unit (OBU) within the communications zone
and must take steps to limit the Roadside Unit (RSU) signal within the
zone to the maximum extent practicable.
(b) Frequencies available for assignment to eligible applicants within
the 5850-5925 MHz band for RSUs and the maximum EIRP permitted for an
RSU with an antenna height not exceeding 8 meters above the roadway bed
surface are specified in the table below. Where two EIRP limits are
given, the higher limit is permitted only for state or local
Channel No. Frequency range
(MHz) Max. EIRP^1
(dBm) Channel use
170 5850-5855 Reserved.
172 5855-5865 33 Service Channel.^2
174 5865-5875 33 Service Channel.
175 5865-5885 23 Service Channel.^3
176 5875-5885 33 Service Channel.
178 5885-5895 33/44.8 Control Channel.
180 5895-5905 23 Service Channel.
181 5895-5915 23 Service Channel.^3
182 5905-5915 23 Service Channel.
184 5915-5925 33/40 Service Channel.^4
^1An RSU may employ an antenna with a height exceeding 8 meters but not
exceeding 15 meters provided the EIRP specified in the table above is
reduced by a factor of 20 log(Ht/8) in dB where Ht is the height of the
radiation center of the antenna in meters above the roadway bed
surface. The EIRP is measured as the maximum EIRP toward the horizon or
horizontal, whichever is greater, of the gain associated with the main
or center of the transmission beam. The RSU antenna height shall not
exceed 15 meters above the roadway bed surface.
^2Channel 172 is designated for public safety applications involving
safety of life and property.
^3Channel Nos. 174/176 may be combined to create a twenty megahertz
channel, designated Channel No. 175. Channels 180/182 may be combined
to create a twenty-megahertz channel, designated Channel No. 181.
^4Channel 184 is designated for public safety applications involving
safety of life and property. Only those entities meeting the
requirements of § 90.373(a) are eligible to hold an authorization to
operate on this channel.
(c) Except as provided in paragraphs (d) and (e) of this section,
non-reserve DSRCS channels are available on a shared basis only for use
in accordance with the Commission's rules. All licensees shall
cooperate in the selection and use of channels in order to reduce
interference. This includes monitoring for communications in progress
and any other measures as may be necessary to minimize interference.
Licensees of RSUs suffering or causing harmful interference within a
communications zone are expected to cooperate and resolve this problem
by mutually satisfactory arrangements. If the licensees are unable to
do so, the Commission may impose restrictions including specifying the
transmitter power, antenna height and direction, additional filtering,
or area or hours of operation of the stations concerned. Further the
use of any channel at a given geographical location may be denied when,
in the judgment of the Commission, its use at that location is not in
the public interest; use of any such channel may be restricted as to
specified geographical areas, maximum power, or such other operating
conditions, contained in this part or in the station authorization.
(d) Safety/public safety priority. The following access priority
governs all DSRCS operations:
(1) Communications involving the safety of life have access priority
over all other DSRCS communications;
(2) Subject to a control channel priority system management strategy
(see ASTM E2213-03 DSRC Standard at § 188.8.131.52(4)), DSRCS communications
involving public safety have access priority over all other DSRC
communications not listed in paragraph (d)(1) of this section. Roadside
Units (RSUs) operated by state or local governmental entities are
presumptively engaged in public safety priority communications.
(e) Non-priority communications. DSRCS communications not listed in
paragraph (d) of this section, are non-priority communications. If a
dispute arises concerning non-priority communications, the licensee of
the later-registered RSU must accommodate the operation of the early
registered RSU, i.e., interference protection rights are
date-sensitive, based on the date that the RSU is first registered (see
§ 90.375) and the later-registered RSU must modify its operations to
resolve the dispute in accordance with paragraph (f) of this section.
(f) Except as otherwise provided in the ASTM-DSRC Standard (see
§ 90.379) for the purposes of paragraph (e) of this section,
objectionable interference will be considered to exist when the
Commission receives a complaint and the difference in signal strength
between the earlier-registered RSU and the later-registered RSU
(anywhere within the earlier-registered RSU's communication zone) is 18
dB or less (co-channel). Later-registered RSUs causing objectionable
interference must correct the interference immediately unless written
consent is obtained from the licensee of the earlier-registered RSU.
[ 71 FR 52749 , Sept. 7, 2006, as amended at 72 FR 35199 , June 27, 2007]
Goto Section: 90.375 | 90.379
Goto Year: 2020 |
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